French scientists who in 2012 wrote a contested study linking pesticide-treated, genetically-modified corn with cancer in lab rats returned to the attack on Tuesday, republishing their work online.
Denying accusations of bad science, the team said the work, which was withdrawn by the journal which first printed it, had been republished in Environmental Sciences Europe, owned by Germany's Springer group.
The raw data has also been placed in the public domain for others to scrutinize, the researchers said.
"Censorship of research into the risks of a technology so intertwined with global food safety undermines the value and credibility of science,'' the team said in a statement.
The research kicked up a hornet's nest when it was first published in September 2012.
Its authors, led by Gilles-Eric Seralini, a professor at the University of Caen in Normandy, said rats fed NK603 corn and Roundup weedkiller developed liver and kidney disease and mammary tumors.
Many other scientists said at the time that the study was flawed. And commentators on Tuesday said nothing has changed through publishing it again.
NK603, made by the US agribusiness giant Monsanto, has been engineered to be immune to the weedkiller Roundup. As a result, farmers can spray their fields to kill weeds without harming their crops.
The authors stood by their original research on Tuesday and lashed out at the journal Food and Chemical Toxicology for withdrawing it -- a great humiliation in the scientific world.
"Roundup formulations and Roundup-tolerant GMOs should be considered as (hormonal) disruptors and their present assessments on health are drastically deficient,'' they wrote. --AFP